Reverse flow spin-cleaning liquid filters

ABSTRACT

A liquid filtering device having a pack of cylindrical filter member discs ( 70 ) with an arrangement for reversed, filter flushing flow cycles. An integrally formed filter core ( 24 ) is provided comprising tubular nozzled conduits ( 30   a   , 30   b,    30   c ) so that water under pressure within the conduits becomes discharged in jet forms to enable free rotation of the filter discs. One-way valve ( 90 ) in the form of a funnel shaped rubber sleeve allows the flow of filtered water to the outlet port ( 20 ) but impedes the flow of flushing water from the outlet port through the filter member ( 70 ) in the direction of the inlet port ( 16 ).

BACKGROUND OF THE INVENTION

The present invention relates to liquid filters, particularly for waterirrigation systems, however also useful for other industrial or domesticapplications.

More specifically, the invention concerns filter devices of the typedisclosed in our U.S. Pat. No. 4,655,910 issued Apr. 7, 1987, thecontents of which is hereby incorporated by reference (hereinaftercalled “the Patent”).

The Patent has introduced for the first time the concept of using filterdevices—in particular of the type utilizing a battery of filterdiscs—with reverse flushing water flow cycles wherein the discs werecaused to spin under the impact of water jets impinging thereon(hereinafter referred to as “Spin-Clean Filters”).

The various constructional examples disclosed in the Patent had incommon a centrally extending conduit serving the dual function ofleading the flushing water to a series of nozzles provided thereon, andof supporting the spinning movement of the discs.

This feature of construction presented, however, certain disadvantages:the operation of the hydraulic cylinder system, responsible forrelieving the pack of discs from the compact, filtering position, wasmainly dependent upon the level of back-pressure applied by the reversewater flow, dictated, among others, by a relatively large diameterpiston; rather cumbersome valve means had to be used for directing thereverse flow of water into the nozzled conduit; and generally—anexcessive number of parts and components had to be used, causingrespective increase of the manufacture, assembly and maintenance costsof the product.

It is thus the general object of the present invention to overcome theabove-listed deficiencies of the conventional spin-clean filters.

It is a further object of the invention to simplify the design of thespin-clean filters, by providing a core member of the filter device of aunitary and integral construction, readily produced by plasticsinjection molding process, that will effectively serve the combinedfunctions of:

generating the water jets;

supporting the revolving movement of the filter discs (or integralfilter member of different types such as screen filters);

providing convenient access to the hydraulic piston assembly by externalpressure control means;

forming a seat for a simple, elastic sleeve-type valve member responsiveto the oppositely directed water flows during the filtering and theflushing modes of operation, respectively; and

providing a centrally extending tube through which pressure commands areadmitted for the operation of the hydraulic piston, controlling thedisengagement of the filter discs.

It is a still further object of the invention to provide a filter devicewith one or more jets generating conduits which extend off-centrallyrelatively to the axis of the filter member, along and adjacent to ageneratrix line thereof.

It is a still further object of the present invention to provide aribbed structure for supporting the spinning motion of the filterelement(s) independently of jet generating conduit(s).

SUMMARY OF THE INVENTION

It is therefore proposed according to the present invention to provide aliquid filtering device, particularly for irrigation water installationsof the type comprising a cylindrical housing with an inlet port and anoutlet port and a cylindrical filter member installed within the housingso that water flowing from the inlet to the outlet enters the filtermember in a radial direction, and discharged through the outlet port,and vice-versa during a reversed, filter flushing flow cycles, thedevice comprising a filter core member centrally mounted within thecylindrical space defined by the filter member, the core membercomprising at least one tubular conduit extending within, adjacent to,and along a generatrix line of the filter member, the conduit beingclosed at one end and in free communication with the outlet port throughits other end; a series of nozzles associated with the conduit so thatwater under pressure within the conduit becomes discharged in jet formsand a filter support structure configured to enable free rotation of thefilter member therearound; one-way valve means adapted to allow the flowof filtered water from the filter member to the outlet port but toimpede the flow of flushing water from the outlet through the filter inthe reverse direction; a fixed member at one side, and a displaceablemember at the other side of the filter member; means for urging thedisplaceable member against the filter member to clamp same between thedisplaceable and the fixed members; hydraulic activating meansassociated with the displaceable member and external controllablepressure means operatively coupled to the displaceable member, thearrangement being such that upon a pressure command by the pressuremeans, the displaceable member is moved away from the filter member torelieve the clamping engagement thereof, and upon application of thefilter flushing flow the water jets are sprayed to rinse the filtermember.

According to a preferred embodiment of the invention, the filter coremember is integrally formed by plastics injection molding process.

BRIEF DESCRIPTION OF THE DRAWINGS

These and additional constructional features and advantages of thepresent invention will become more clearly understood in light of theensuing description of a preferred embodiment thereof, given by way ofexample only, with reference to the accompanying drawings, wherein

FIG. 1 is a longitudinal cross-sectional view of a filter deviceaccording to a preferred embodiment of the invention shown in thenormal, filtering mode of operation;

FIG. 2 is an exploded cross-sectional view of the filter assembly ofFIG. 1;

FIG. 3 is a section taken along line 3—3 of FIG. 1;

FIG. 4 is a section taken along line 4—4 of FIG. 1;

FIG. 5 is a section taken along line 5—5 of FIG. 1;

FIG. 6 is a sectional view taken along line 6—6 of FIG. 1;

FIG. 7 is a section taken along line 7—7 of FIG. 1;

FIG. 8 is a section taken along line 8—8 of FIG. 1;

FIG. 9 is a perspective view of a rubber sleeve one-way valve employedin the filter of FIG. 1;

FIG. 10 shows the filter device of FIG. 1 in the reverse flush flow,spin-cleaning mode of operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, the filter device generally designated 10comprises a two-member housing, namely, the first dome-shaped covermember 12 and second inlet/outlet ports member 14.

The housing members are mounted to each other in any conventional mannersuch as tightening bands or the like (not shown). The second housingmember 14 comprises inlet port 16, preferably with a first pressuregauge nipple 18 for measuring inlet pressure conditions; and outlet port20 with a second pressure gauge nipple 22.

The integral main filter core member generally denoted 24 (see FIG. 2)comprises the following sub-structure components: a centrally extending,pressure commands communication tube 26, which leads to hydraulic pistonsystem assembly, generally denoted 28, as will be described below; anarray of three, off-centrally located flushing nozzled conduits 30 a, 30b and 30 c (see FIG. 3) each provided with a plurality of jet-formingnozzles denoted N; a structure comprised of three filter-supportingvanes 32 a, 32 b, 32 c; a cone-shaped valve-seat cavity walls 34 (seeFIG. 2) with a plurality of filtered water discharge slits S deployedaround an intermediate wall portion thereof; a fixed element backingflange 36, combined with mounting screw-threaded ring 38; a firstcylindrical cavity 39; and a second, concentrical, cavity 40, the latterforming the piston cylinder 40 for hydraulic or pneumatic piston 58, aswill be explained below.

Further notice should be taken of three passages 42 (only one seen inFIGS. 1 and 2) and three or more screw-receiving bores 44—the majorpoint being that the core member 24, including all the above-detailedparts and components, can readily be manufactured, as a one-piece, solidarticle, by state-of-the-art plastics injection molding process.

Reference shall now be made to the hydraulic (or pneumatic) cylinder andpiston system assembly 28, seen in FIG. 1, and more clearly in FIGS. 2,7 and 8. In the present example, it comprises a coil spring 52,compressed between rim 54 a of perforated base 54 b of cross-shaped rod54 (so that water can uninterruptedly flow therealong), and disc 56fastened by self-tapping screws 56 a driven into the pre-formed screwreceiving bores 44.

Piston 58 with sealing gasket 58 a (see FIG. 1) is slidable within thesecond concentrical cavity, which formed the piston cylinder denoted 40.A cap member 60 is dressed over the piston cylinder 40, tightened to thepiston 58 by butterfly nut 62 fastened to bolt thread portion 54 c ofthe cross-shaped rod 54.

The cap member 60 possesses a cap flange 60 a, forming the counter-partof the fixed element backing flange 36, and comprises the displaceablehydraulic piston system assembly 28, achieving the relief of theclamping of filter discs battery generally denoted 70.

Referring back to the leading end of the integral main filter coremember 24 (FIGS. 1, 2 and 6), it is seen that the mountingscrew-threaded ring 36 is coupled to an intermediate mounting fitting 80via ring 82 (with O-rings 80 a and 80 b), and is thus mounted to andforms an extension of the outlet port 20.

In-between, a funnel-shaped sleeve, serving as one-way valve 90 isprovided, fitting into the cone-shaped valve-seat cavity walls 34, (seeFIG. 2)—having three mounting legs 90 a, 90 b and 90 c (see FIG. 9).Three cut-out portions 90 d, 90 e and 90 f (not shown) are made, so thatin the assembled position the openings of the tubes 30 a, 30 b and 30 cwill remain open, while the outlet slits S of cone-shaped valve-seat:cavity walls 34 are elastically sealed.

Mounting of the funnel-shaped valve 90 is conveniently attained byinsertion of the legs 90 a-90 c through the passages 42 left for thatpurpose during the molding of the integral main filter core member 24.

The rubber funnel-shaped valve 90 is preferably made of Latex rubber orequivalent synthetic elastic material.

Finally, the pressure control commands leading tube 26 is extended as byan L-shaped tubular member 80 c, preferably integrally molded with theintermediate mounting fitting 80 (see FIG. 6). Communication to thepressurized fluid (hydraulic or pneumatic) source (not shown) is thencompleted by extension tube 100 with nipple 100 a projecting from thewall of the housing inlet-outlet ports member 14.

The operation of the filter device 10 will be now described withreference to FIGS. 1 and 10. Water to be filtered is admitted throughthe inlet port 16, surrounds the integral main filter core member 24with filter discs battery 70, penetrates through said filter discsbattery 70, pushes its way through the slits S by deforming inwardly theone-way funnel-shaped sleeve valva 90, and becomes discharged throughthe outlet 20.

It should be noticed, that at this, normal filtering operational stage,the pressure prevailing within the filter is the outlet pressure, namelyclose to the atmospheric; and that no pressure command is applied to thepiston system 28. Therefore, the force applied by the cap member 60 onthe filter discs battery 70 equals to the inlet pressure (usually about3-5 atm.) multiplied by the (projected) area of the piston 58 plus theforce of the compression spring 52.

The flushing cycle proceeds as follows (see FIG. 10). The inlet flow isfirst interrupted, relieving the piston 58 from the inlet pressure(while the force of the compression spring 52 is still applied). It isthe pressure command delivered from the control system (not shown),through the nipple 100 a, tube 80 c, tube 26, and around thecross-shaped rod 54, that causes the displacement of the piston 58 (andcap member 60) away (to the left of the drawing, see FIG. 10), and thusthe release of the filter discs battery 70 from the previous compactstate is achieved, as a preparatory stage before their spin-cleaning.

Flushing water is admitted through the outlet port 20, freely enteringthe nozzled conduits 30 a-30 c (see FIG. 2) and discharged in inclinedjet forms against the filter discs 70, to perform the spinning andrinsing operation. The discs are free to revolve about the edges of thethree vanes 32 a-32 c (see FIG. 3) (although the option to support thediscs directly by the nozzled conduits 30 a-30 c is also available).

Water does not reach the inner space of the skeleton-like core member,since the wall of the elastic funnel-shaped sleeve valve 90 becomespressed against the cone-shaped valve-seat cavity walls 34, sealingthereby the water discharge slits S.

The rinsing stage operation is thus completed independent of theflushing, reverse flow pressure level, as far as the displacement of thecap member 60 is concerned—in distinction to the state of the artdevices including those of our Patent.

It will be thus appreciated by those skilled in the art that theconstruction proposed according to the invention is advantageous in therelevant respect of production technology, number of parts and assemblycosts, and maintenance requirements, mainly due to the unique structureof off-central location of the jet generating nozzled conduit(s) 30.

While the above description contains many specificities, these shouldnot be construed as limitations on the scope of the invention, butrather as an exemplification of preferred embodiments. Those skilled inthe art will envision other possible variations that are within itsscope. Accordingly, the scope of the invention should be determined notby the embodiment illustrated, but by the appended claims and theirlegal equivalents.

Thus, for example even a single jet-generating nozzled conduit 30 maysuffice, however, three, of course, present more symmetric and balancedconstruction. Furthermore, the spin-supporting function can be fulfilledby the nozzled conduits 30 properly, without the need to provide for thevanes 32 altogether.

What is claimed is:
 1. A liquid filtering device, particularly forirrigation water installations of the type comprising: a cylindricalhousing with an inlet port and an outlet port; a cylindrical filtermember installed within the housing so that, water flowing from theinlet port to the outlet port enters the filter member in a radialdirection, and is discharged through the outlet port, and vice-versaduring reversed, filter flushing flow cycles; a core member centrallymounted within the cylindrical space defined by the filter member, andintegrally formed to include at least one tubular conduit extendingoff-centrally along an internal generatrix line of the filter member andprovided with a series of nozzles for ejecting jets in the direction ofthe filter member during said reverse filter flushing flow cycles, asupport for the filter member, and a fixed member abutting against thefilter member at one axial side thereof; a cylinder-and-piston assemblymounted to the core member, comprising a displaceable member abuttingagainst the filter member at the other axial side thereof; and means forapplying pressure to the assembly whereby the displaceable memberbecomes displaced away of the fixed member.
 2. A liquid filteringdevice, particularly for irrigation water installations of the typecomprising: a cylindrical housing with an inlet port and an outlet port;a cylindrical filter member installed within the housing so that, waterflowing from the inlet port to the outlet port enters the filter memberin a radial direction, and is discharged through the outlet port, andvice-versa during reversed, filter flushing flow cycles; a core membercentrally mounted within the cylindrical space defined by, and forming asupport for, the filter member; a fixed member abutting against thefilter member at one axial side thereof; a piston assembly mounted tothe core member, comprising a piston and a displaceable member coupledto the piston and abutting against the filter member at the other axialside thereof; and means for applying pressure to the assembly wherebythe displaceable member becomes displaced away of the fixed member, andat least one tubular conduit extending off-centrally, along an internalgeneratrix line of the filter member, and provided with a series ofnozzles for ejecting jets in the direction of the filter member duringsaid reverse filter flushing flow cycles; wherein the core member isintegrally formed and comprises a cavity that forms a cylinder for thepiston of the piston assembly.
 3. The device as in claim 2, wherein thecore member is formed with an elongated tube communicating at one endthereof with the cavity and at the other end with the pressure applyingmeans.
 4. The device as claimed in claim 3, wherein the core membercomprises a structure configured to freely support the filter memberupon being released by the displaceable member.
 5. A liquid filteringdevice, particularly for irrigation water installations of the typecomprising: a cylindrical housing with an inlet port and an outlet port;a cylindrical filter member installed within the housing so that, waterflowing from the inlet port to the outlet port enters the filter memberin a radial direction, and is discharged through the outlet port, andvice-versa during reversed, filter flushing flow cycles; a core membercentrally mounted within the cylindrical space defined by, and forming asupport for, the filter member; a fixed member abutting against thefilter member at one axial side thereof; a cylinder-and-piston assemblymounted to the core member, comprising a displaceable member abuttingagainst the filter member at the other axial side thereof; and means forapplying pressure to the assembly whereby the displaceable memberbecomes displaced away of the fixed member, wherein the core member isintegrally formed and comprises at least one tubular conduit extendingoff-centrally, along an internal generatrix line of the filter member,and provided with a series of nozzles for ejecting jets in the directionof the filter member during said reverse filter flushing flow cycles;and wherein the core member is formed with a cone-shaped cavity providedwith passages, the cavity forming a seat for a one-way valve, made of anelastic material, being funnel shaped to fit into the cavity and havinga wall portion configured to elastically close against the passages, andcut-out portions exposing the openings of the conduits to communicatewith the outlet port.
 6. The device as claimed in claim 5, wherein thevalve is provided with at least one axially extending leg, the coremember being further formed with at least one recess configured toreceive said leg for mounting the valve to the core member.